Terminal of the grommet type



June 23, 1953 Q. BERG I TERMINAL OF THE GROMMET TYPE Filed Feb. 12, 19497. INVENTOR BY, QOf/VT/N 559 Patented June 23, 1953 UNITED STATES PATENTOFFICE TERMINAL OF THE GROMME'I TYPE Quentin Berg, New Cumberland, Pa.,assignor to Aircraft-Marine Products Inc., Harrisburg, Pa.

Application February 12, 1949, Serial No. 76,070

4 Claims.

This invention relates to electrical terminals and to methods of makingand applying them, and to electrical connections made by use of suchterminals.

When the maximum dimension of an electrical terminal must be maintainedvery small, it has been common practice to use various types of eyelets.Most of these eyelets merely had a tu bular portion at their center withan annular flange extending therefrom. In use, an electrical conductoror wire was looped around this tubular portion or the strands of astranded conductor split and wrapped around bi-laterally, and thetubular portion (with or without breaking into fingers) was forced downand outward and compressed onto the wire. Such eyelets were generallyrecognized as inferior terminals having relatively poor electrical andmechanical characteristics. In an effort to improve these eyelets thecompressed assemblies were usually dipped in solder to provide them withgreater strength and electrical stability.

Besides these disadvantages. eyelet type terminals found in the priorart could not utilize the sheet metal stock from which they were madeeconomically.

An object of this invention is to provide compact electrical terminalswhich have inherently greater mechanical strength and electricalconductivity than has been obtained with eyelet terminals in the priorart, and which therefore do not require soldering.

A further object of this invention is to provide an electrical terminalof small maximum radius which utilizes relatively greater percentage ofthe sheet metal stock from which it is made.

A third object is to provide electrical terminals which satisfy thepreceding objects and which can be made as an integral strip and whichcan be left in such strip until they are applied to the ends of wires,whereupon they may be easily severed from the strip.

Yet another object of this invention is to provide terminals in stripform, as described above, which are adapted to be used in automaticapplying and severing machines.

Other objects will be apparent from the fllowing description and claims.

These various objects are met by my novel method of making a termina1 ofthe eyelet type from a rectangular sheet metal blank in which aterminated wire is enclosed between an annular base and ears folded fromboth the inner and outer peripheries of the annulus.

In this specification and the accompanying drawings are shown anddescribed a preferred embodiment of the invention and variousmodifications thereof. It is to be understood that these are notintended to be exhaustive nor limiting of the invention, but on thecontrary are given principally for purposes of illustration in orderthat others skilled in the art may fully understand the invention and1the principles thereof and the manner of applying it in practical useso that they may modify and adapt it in various forms, each as may bebest suited to the conditions of a particular use.

In the accompanying drawings:

Figure l is a perspective view of a terminal constructed according tothis invention and crimped on the end of a wire;

Figure 2 is a perspective view of a terminal shown in Figure 1 prior toits being crimped on the end of a wire, with other terminals of a stripor continuous series of them shown in phantom lines;

Figure 3 is a top plan view of a strip of sheet metal showing variousstages in the formation of terminals, of the type shown in Figures 1 and2, according to this invention;

Figure l is a perspective view of a second embodiment of this invention;

Figure 5 is a top plan view similar to Figure 3 but of a thirdembodiment of this invention; and

Figure 6 is a perspective view of the embodiment constructed accordingto Figure 5.

Referring to Figure 1, the terminal structure 2 shown has outer ears 4compressively turned inward and crimped on an electrical conductor orwire 6 looped into an annular channel I, while inner ears 8 aresimilarly turned outward over the wire 6 and crimped thereon. Note that,in the embodiments shown in Figures 1 through 4, the inner ears 8 areperipherally alternated with respect to the outer ears 4 and thus theinner and outer ears neatly intermesh with one another and almosttotally enclose the wire 6, as is shown in Figure 1. This removes one ofthe serious objections to eyelets in the prior art, namely the escape ofstrands or whiskers which can make accidental contact with other parts.

Figure 2 shows a terminal of the type shown in Figure l, but beforecrimping and prior to a wire being inserted therein. As shown in Figure3, this termina1 may be formed from rectangular sheet metal blanks by aseries of stamping operations. Figure 3 shows the blanks. 20 themselvesbeing formed from a strip of sheet 3 metal l2, which in effect is anintegrally connected series of such blanks.

In the operation designated generally as in Figure 3, small pieces arestamped out of the metal strip I2, leaving triangular holes [4. In thenext operation IS the strip is cut laterally beyond the holes l4,producing the end edges 18 of rectangular blanks 20 and, with thecutting means presently employed, a slight fold 24 is formed in one endmargin of the blank 20.

The purpose of the triangular holes I4 is to so shape the cornerportions I3 that they will leave an opening between them, when folded toform ears 4, sufficient to permit the wire 6 to enter said openingwithout a tendency to be cut by the edges of the terminal when crimped.This is best understood from Figure l. The triangular openings l4 can beextended out to the side edge l5 of the metal strip 12, thus avoidingthe need for the separate cutting step described above as part of theoperation designated l6. Also, in order to produce a straight end edgel8 at one end of the metal blanks 20, the triangular openings [4 mayhave one side perpendicular to the side edge [5 of the strip l2. Theoperation It also includes the step wherein crossed cuts or weakenedlines 22 are stamped in the bottom of the blank 20 approximately on thediagonals of the blank. As shown, the lines 22 are not cut through, butleave the blank strong enough to withstand a shallow drawing operation26, wherein the area of the crossed cuts 22 is stamped into the shape ofan inverted shallow cup 28.

This cupped area 28 is not essential to utilization of this invention inits more basic aspects, but is advantageous with the relative dimensionsshown for obtaining more complete enclosure of a wire 6 (referring toFigure 1) by the two sets of ears 4 and 8. As will be seen, this step offorming a shallow cup 28 (Figure 3) in the area of the cuts 22 produceslonger inner ears 8 than if the sheet metal blank 20 were left flat.

The final operation, shown generally at 30, consists of folding up thefour corner portions l3 of the blank 20 to form the outer ears 4, andsevering the bottom of the cup 28 at the cuts 22 and opening, likepetals of a flower, the four inner ear portions 8.

It will be noted that, in Figures 2 and 3, the side edges of the blankare folded up with the outer ears 4, a construction which not onlyprovides a better annular channel I for receiving a wire 6, but alsostrengthens the structure 2, particularly in respect to the outer ears4. The folds 29 which join the ears 4 and 8 to the annular channel I areshown as smoothly curved in two senses, that is, curved across the foldas well as along the fold, creating the channel I of rounded crosssection and of generally round shape. Such compoundly-curved folds helpto minimize the size of the terminal by giving it, when crimped on aWire, a generally round shape with a rounded aperture 9 (Figure 1)adapted to closely fit a round screw, bolt, binding post, or other maleterminal member. Further, the annular channel 1 of rounded cross-sectionis adapted to closely fit a wire received therein, as well as being ofgreater strength than a fiat base. These curves, however, are notessential; for some uses, the terminal may have a fiat bottom with theears 4 and 8 rather sharply folded up from this flat bottom.

For some purposes, terminals of small dimension which securely grip theinsulation on the wire connected thereto are desired. Figure 4 shows anembodiment of this invention which incorporates an insulation-supportferrule-forming portion 34 with the terminal structure 2 as describedabove. In use, a wire loop is inserted in the annular channel 1, the twosets of cars 4 and 8 compressed over it, and the ferrule-forming portion34 compressed on the wire insulation in such a fashion as to grip itsecurely against being pulled back from the terminal assembly.

After inserting a wire wrapped in a loop to fit the annular channel 1,the crimping Of a terminal structure 2 as shown in Figure 2 to form awire terminal as shown in Figure 1 can be done by a pair of annularconcave crimping dies, a cylindrical male die which fits into a conicalfemale die being advantageous for this operation. With dies of thelatter type, the female member is advantageously used to draw the ears 4and 8 inward and crimp them on the wire.

In order to utilize this invention on Wire which has not been previouslystripped of its insulation, the peripherally alternated ears 4 and 8, ormodifications thereof, may be so curled that their ends are driveninward and down against a wire placed in the annular channel I withradii of curvature of rolled inward portions such that these cars piercethe wire insulation and contact the central conductor core of the wire.The means of doing this could be similar to those disclosed and claimedin the Hackbarth Patent 2,302,767, issued November 24, 1942.

Though there are great advantages to be derived from the terminalstructure 2 shown in Figures 1 through 4, a second form of construction2b is shown in Figures 5 and 6 wherein the inner ears 8?) are radiallyopposed to the outer ears 4, rather than alternated. Figure 5 shows theformation of the structure 2b with this different arrangement of theinner ears 4, with steps similar to those discussed above in referenceto Figure 3.

The terminal structure 2b can be attached to a loop in a wire 6 byfolding radially opposed pairs of ears 4 and 8b toward each other,enclosing a wire 6, and further so curling the ears toward each other sothat their abutting edges are driven down into the strands of a strandedwire until the assembly is sufhciently compacted to provide a securephysical and electrical connection. The cross section of a crimp Of thistype provides a broadly curved bottom periphery and a top with twoabrupt curves side by side, as is shown in the copending application ofJames C. Macy, Serial No. 717,842, filed December 23, 1946,

Another way of applying this second form of terminal 2b would be to rollthe outer and inner ears 4 and 822 over the wire in such a fashion thatthe ears of one set are clamped over those of the radially opposed set.

Various forms of terminals constructed according to my invention haveadvantages which are important though not immediately apparent. One ofthese is that such terminals have substantially the same metal thicknessthroughout, and thus, for a given maximum metal thickness, are strongerthan the eyelets of the prior art.

Another advantage of my invention is that the strands of a stranded wireare picked up, gathered together, and drawn into the annular channel andthen tightly enclosed by the inner and outer ears during a crimpingoperation with a comically-walled, concave, annular female crimping dieas discussed above.

I claim:

1. An electrical connector which includes an annular base, four earportions extending upward from each of the inner and the outerperipheries of said annular base, the said ear portions extending fromthe outer periphery being generally triangularly shaped and defined attheir tips by substantially right angles.

2. An electrical connector comprised of an an nular base, four earportions extending upfrom each of the inner and outer peripheries ofsaid annular base, said ear portions being generally triangularly shapedand defined at their tips by substantial-1y right angles, said connectorstructure being characterized by the fact that it is formed of a metalsheet of generally rectangular shape.

3. An electrical connector as defined in claim 2 in which the altitudeof the triangle of said ear portions from said tips to the periphery ofReferences Cited in the file of this patent UNITED STATES PATENTS NumberName Date 950,524 Whytock, Jr Mar. 1, 1910 1,044,283 Stanger i Nov. 12,1912 FOREIGN PATENTS Number Country Date 96,422 Austria Mar. 26, 1924

